As computers and computer networks become ubiquitous, more and more transactions are being conducted over computer networks. Various mechanisms and procedures have been implemented in order to make such transactions secure and in order to verify and authenticate the parties involved. Often, such verification and authentication requires the user to input information that the user may not readily remember, is intrusive, or is not easily accessible to the user. Accordingly, requiring the user to input such information impedes the transaction and adversely affects the user experience, which may cause fewer transactions to be conducted over computer networks.